User generated content’s new frontier, book publishing, is expanding even further.

When self-published authors make their e-books available exclusively on Kindle for 90 days, Amazon is allowing them to add their books to the Kindle Owners’ Lending Library, which gives them a chance to earn extra money.

This is part of the new KDP Select, an annual US$6 million fund for Kindle Direct Publishing Authors and Publishers, which gives independent authors and publishers a way to reach more readers and royalties, Amazon said in a statement. The authors can earn money from the $6 million fund when they agree to the deal. The fund for this month is $500,000.

Authors can enroll a single book, select items or their entire catalog.

Amazon launched the Kindle Owners’ Lending Library last month. With this system, customers with a yearly $79 Amazon Prime membership and a Kindle device can borrow e-books for free. They are limited to one e-book per month, one at a time, and any notes or bookmarks are saved if the reader re-borrows the book later on, PCMag reported.

“By choosing KDP Select, independent authors and publishers have an opportunity to make money in a whole new way and reach the growing audience of Amazon Prime members,” Russ Grandinetti, vice president of Kindle Content, said in a statement. “A short 90-day commitment allows authors and publishers to experiment at very low risk. In addition, free promotions are a new tool for KDP Select authors, and we hope to add more such tools over time.”